平板电解槽内电解质湍流运动和传质的直接数值模拟

应用流体动力学、传质学和电化学理论,建立三维电解槽二元电解质溶液湍流运动的物理和数学模型,针对Butler-Volmer定律下极限电流和恒电流两种情况,通过直接数值模拟研究电解质溶液传质和运动特性,分析不同Schmidt数对电解质溶液平均浓度和脉动浓度的影响,考察湍流的脉动量控制电沉积的过程规律.对瞬时脉动浓度云图的分析可知,在高Schmidt数下脉动浓度拟序结构间距密集,且集中在壁面附近,表明高Schmidt数下传质过程主要由近电极处薄层内的流动行为所主导.

Numerical Simulation of Turbulent Mass Transfer of Binary Electrolyte in an Electrode Channel

Direct numerical simulations of binary electrolyte in an electrode channel with turbulent mass transfer are performed under limiting current condition and galvanostatic current conditions. Behaviors of turbulent concentration diffusion from electrodes to adjacent electrolyte in a wide range of Schmidt numbers are examined and mechanism of turbulent mass transfer in electrolytic processes is analyzed. A physical model for turbulent electrodes channel flow is established with electrochemistry theories as well as fluid dynamics. Effect of Schmidt numbers on turbulent mass transport, mean and fluctuating concentrations, mass transfer coefficient, Sherwood numbers, and instantaneous structures of concentration fields are exhibited and analyzed. It shows that mass transfer at electrodes in turbulent electrolyte is sensitive to current conditions.